netdev - Re: [PATCH 8/8] dm-verity: Convert from tasklet to BH workqueue

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Message-ID: <ZbrgCPEolPJNfg1x@slm.duckdns.org>
Date: Wed, 31 Jan 2024 14:04:24 -1000
From: Tejun Heo <tj@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Mikulas Patocka <mpatocka@...hat.com>, linux-kernel@...r.kernel.org,
	dm-devel@...ts.linux.dev, msnitzer@...hat.com, ignat@...udflare.com,
	damien.lemoal@....com, bob.liu@...cle.com, houtao1@...wei.com,
	peterz@...radead.org, mingo@...nel.org, netdev@...r.kernel.org,
	allen.lkml@...il.com, kernel-team@...a.com,
	Alasdair Kergon <agk@...hat.com>, Mike Snitzer <snitzer@...nel.org>
Subject: Re: [PATCH 8/8] dm-verity: Convert from tasklet to BH workqueue

Hello, Linus.

On Wed, Jan 31, 2024 at 03:19:01PM -0800, Linus Torvalds wrote:
> On Wed, 31 Jan 2024 at 13:32, Tejun Heo <tj@...nel.org> wrote:
> >
> > I don't know, so just did the dumb thing. If the caller always guarantees
> > that the work items are never queued at the same time, reusing is fine.
> 
> So the reason I thought it would be a good cleanup to introduce that
> "atomic" workqueue thing (now "bh") was that this case literally has a
> switch between "use tasklets' or "use workqueues".
> 
> So it's not even about "reusing" the workqueue, it's literally a
> matter of making it always just use workqueues, and the switch then
> becomes just *which* workqueue to use - system or bh.

Yeah, that's how the dm-crypt got converted. The patch just before this one.
This one probably can be converted the same way. I don't see the work item
being re-initialized. It probably is better to initialize the work item
together with the enclosing struct and then just queue it when needed.

Mikulas, I couldn't decide what to do with the "try_verify_in_tasklet"
option and just decided to do the minimal thing hoping that someone more
familiar with the code can take over the actual conversion. How much of user
interface commitment is that? Should it be renamed or would it be better to
leave it be?

Thanks.

-- 
tejun